That's the part I don't get. The rule is if the momentum of the catch takes you to the ground, you have to maintain possession thru landing on the ground. I think Dez did, but reached for the goalline. Basically, they are saying this was all 1 motion, in which case that would be a correct interpretation of the rule. The steps dont matter because he wasn't running on his own. He was stumbling toward the ground (due to the momentum of the catch). Dez should have just hit the ground and not tried to reach for the end zone, then he would have never lost it. I think you should be able to seperate the 2 different motions, but the rules don't allow that.